Overload release mechanism



Oct. 1 1,' 1949.

H. c. NISVSEN OVERLOAD RELEASE MEGYIANISM 3 SIiBecs-Sheet 1 Filed Jan. 10, 1946 Oct. .11, 1949. H. c. NISSEN 2,434,793

OVERLOAD RELEASE MECHANISM FiledJan. 10, 1946 I '5 Sheets-Sheet 2 Oct. 11, 1949.-- H, c, ssE 2,484,793

OVERLOAD RELEASE MECHANISM Filed. Jan. 10, 1946 3 Sheets-Sheet 3 Patented Oct. 11, 1949 2,484,793 OVERLOAD RELEASE MECHANISM Henry C. Nissen,

Singer N. J., a corporation Manufacturing f New Jersey Stratford, Conn, assignor to The Company, Elizabeth,

Application January 10, 1946, Serial No. 640,196 9 Claims. (Cl. 112-220) This invention relates to sewing machines and, more'particularly, to sewing machines having a compound needle and lower feed-dog workadva'ncing mechanism, together with a rotary loop=taker of' the 'loc'kstitch type.

'The present invention has for its primary object to obviate breakage of parts upon overload of the rotary'loop-taker of a sewing machine having a compound needle and lower feed-dog work- 'adv-ancing mechanism in which the feed-dog is operatedffrom actuating mechanism disposed below the work=support of' the machine.

v More specifically, the present invention has for anpbj'ect to'jprovide for'continuance of the synchronous, work feeding operation of the needle andlower feed-dog of a compound work-advancmg-mechanism "in which the feed-dog is operated from actuating mechanism disposed below the work=support -of a' sewing machine,- after release 'bf thesewing machine loop-taker from its driving mechanism due to the action 'of the overload release mechanism. 7

Other and more-specific objects of the invenhim will be apparent from the following description and claims.

The invention comprises the devices, combinations and arrangements-cf parts hereinafter described in connection with the accompanying drawings, which illustratea preferred embodiment'o'f the 'inventionand in which:

Fig. l repre'sentsa vertical longitudinal section of a sewing machine containing the present improvements. I

Fi'g. 2 representsa bottom plan view of thesewing machine.

I Fig. 3 represents anenlarged transverse section taken substantiallyon the line3-3of Fig. 1.

s Fig. 4 represents anenlarged transverse section 'taken-subst'antially'on the line 4-4 ofFig. 1.

Fig. 5 is a sectional view taken substantially on the line 55 of Fig. 3.

v [Fig.trepresentsan enlarged transverse section taken substantiallypn the line 66 of Fig. 1.

The sewing machine illustrated .in the drawings has "a frame including a horizontally dispersed Work-support comprising a bed-plate l0 provided with left and right slide-plates ll and 12. Rising from one end of the bed-plate Ill is the hollow standard '13 of a bracket-arm l4 ter- "minating atits free end'in'a head I 5.

Extending longitudinally of and disposed within the bracket-arm M is a horizontally disposed rotary main or arm-shaft it, one end of said shaft carrying a belt-pulley I! and being journaledin 'a ba'll bearing l8 disposed within a bearilig-"boss "I 9 projecting from the bracket-arm 1'4.

end of which is made fast to screw 33. apertures 34 and 3 5 provided in-the wall-sections The main-shaft I6 is journaled in bearing bushings 20 and 2| and, at its end adjacent the bushing 2|, carries acrank 22 connected by the usual link '23 with a needle-bar carrying at its lower end a pair of needles '25 arranged abreast with respect to the direction of feed of the work.

The needle-bar 24 is journale'd' for vertical reciprocation in a pe'ndulous frame 26 pivotally hung'upon a fulcrum-pin 2 for swinging movements within'the head l 5 about an axis substan- 'tially parallel to the axis of rotation-of the mainshaft It.

For imparting swinging or work -feeding movements to the needles 25, there isprovided'an adjustable eccentric 28 on the shaft 1 6. Embracing this eccentric is a p'itman '29 (see Fig. 6) to which is pivotally connected a cran'k3ll, the lower a needle-feed rockshaft 3! by means of the clamp '3 2' and clamp- Rock-shaft "3| is journaled Within of the bracket-arm M. At the forward end of the rock-shaft there is formed a bent crank arm 36 operative'l-y connected to 'the' lower 'endof the pendulous frame '26 to impart vibratory movements thereto about the fulcrum-pin 21. This arrangement provides simple and well-balanced means for transmitting unison work-advancing and return movements to the needles 25. The usual eccentric-adjusting means 31 are provided on shaft l6 for adjusting 'the'throw o'f eccentric 28 so as to vary the amplitude of the work-feeding movements of the needles '25. An adjustable eccentric of this type is fully disclosed in the "U. S. patent to W. Myers,No. 2,128,031, August 23, 1938.

Disposed below and adjacent the rearward'edge of the bed-plate lll, substantially parallel to the main-shaft It, is a primary loop-taker and feedactuating bed-shaft 38. Adjacent one end thereof, the shaft 38 is journaled in a bearing bus'hing 39 sustained by a bearing-lug depending from the bed-plate Ill. Proxima'te to its opposite end, the shaft 38 is 'journaled in a bearing-bushing secured in a lug 42 dependingfrom the bed-plate It. At its free end, adjacent to'the bushing 39, the shaft carries a peripherally grooved beltpulley 43 connected by a clip-belt 44'with a 'similar pulley45, of the same size as said pulley-'43 and carried by'the main-shaft [6, whereby the shaft 38 is driven at the'same speed as said main-shaft Mounted beneath the bed-plate II], in coaxial relation with the shaft 38"is a loop-taker actuating shaft 46. Adjacent itsyend proximate to the '1s'haft"38, the shaft 46 is journaled in a bearingbushing 41 which is secured within a depending lug 48-, and the opposite end of the shaft 46 is journaled in a bearing-bushing 49, which is secured in a depending lug 58.

Carried by the shaft 46, between the bearingbushings 41 and 49, are two spiral-gears and 52 in driving engagement with spiral-gears 53 and 54, respectively, the gear ratios being such that the driven gears 53 and 54 are rotated at twice the speed of the driving gears 5| and 52. The driven gears 53 and 54, are carried by vertically disposed loop-taker shafts 55 and 56, respectively, said shafts being of similar construction and each carrying at its upper end the usual loop-taker elements 56 and 51' respectively, which elements are of the vertical axis rotary hook type.

The loop-taker shaft 55 is journaled in a righthand loop-taker bracket 51, said bracket having at its rearward end a split bearing-boss 58 adjustably clamped upon the bushing 41 by a screw 59. At its forward end, the bracket 51 is provided with a foot 68 having an upper face secured by a screw 6| against a seat afforded by the horizontally flattened lower end of a lug 62 depending from the bed-plate I8. The bracket-securing screw 6| passes through a slot 63 provided in the foot 68, said slot being elongated in a direction to provide for adjustment of the bracket 51 toward and from the path of needle reciprocation.

The loop-taker shaft 56 is likewise journaled in a left-hand loop-taker bracket 64 having at its rearward end a split bearing-boss 65 adjustably clamped by a screw 66 upon the bushing 49. At its forward end, the bracket 64 is provided with a foot 61 having an elongated slot 68 entered by a screw 69 which secures the foot 61 against a horizontal seat formed by suitably recessing a lug 18 depending from the bed-plate I8. For a more detailed description and disclosure of this loop-taker mechanism, reference may be had to the herein before mentioned Patent No. 2,128,031.

Shaft 46 is normally driven directly by shaft 38 through a coupling or overload release clutch 1| (Fig. 3) which will be described in detail hereafter. Thus, rotation of the'belt-pulley I1 will actuate the gears 5| and 52 for the purpose of driving the loop-taker mechanism in the usual manner. 1

The work is intermittently advanced past the stitch-forming mechanism by a so-called compound feeding mechanism including a lower fourmotion or drop-feed and a needle-feed. The usual feed-dog 12 is secured to and carried by a feed-bar 12 provided with a fork 13 engaging a feed-lift actuating eccentric 14 carried by the loop-taker actuating shaft 46, thereby to impart rising and falling movements to the feed-dog. The feed-dog 12 is provided with a pair of needle apertures 25.

The front end of the feed-bar 12' is pivotally secured to the usual feed-rocker 15 which is carried and actuated by a feed-advance rock-shaft 16 journaled in frame lugs 11, 18 and 19 depending from the bed-plate I8. The feed-dog 12 is given its feed-advance and return movements by shaft 16 through the medium of the rocker 15.

The rocking movements are imparted to the feed-advance rock-shaft 16 by the rotary shaft 38 through the medium of a pitman rod 88. The rear end of this pitman rod embraces an adjustable eccentric 8| actuated by the shaft 38 and provided with eccentric-adjusting mechanism 82 similar to the adjusting mechanism of the armshaft I6. The forward end of the pitman 88 is pivotally secured to a depending crank arm 83 clamped upon the shaft 16 by means of a clampscrew 84. Thus, rotation of shaft 38 will impart the usual rocking movements to shaft 16. The lower feed eccentric 8| and the upper or needlefeed eccentric 28 may be adjusted by their respective adjusting mechanisms 82 and 31 to the end that the needles 25 and the lower feed-dog have similar work-feeding amplitudes.

It is the purpose of the above noted overload release clutch 1| to provide means effective, in the event either of the rotary hooks becomes jammed, to disconnect the primary bed-shaft 38 from the shaft 46, whereby the lower four-motion feed continues to operate in unison with the needle-feed, thereby eliminating the possibility of the needles striking the feed-dog and breaking.

The clutch 1| comprises a driving dog having arms 85 and 86 projecting radially from a hub 81 which is mounted upon the forward end of shaft 38 by means of set-screws 88. The free end portions of the arms 85 and 86 extend, respectively, into slots 89 and 98 provided in the flanged periphery of a driven clutch-member 9| which is freely journaled upon the reduced end of a collar 92 secured in turn upon shaft 46 by means of screws 93. The shoulder 94 of the collar 92 and a clutch-setting disk 95, which is secured to shaft 46 by means of a set-screw 96, confine the clutch-member 9| in position and prevent any movement thereof longitudinally of the shaft 46.

The collar 92 has a recess 91 with outwardly diverging inclined sides formed in the periphery thereof for receiving normally a wedge-shaped projection 98 formed on a link 99 which is pivotal-- ly secured at one end by a screw I88 to .the side face of the clutch-member 9|. The other end of the link is pivotally connected to a second link I8I by means of a pin I82 rigidly carried by the link I8I. The opposite end of the link |8I has rigidly secured thereon a second pin I83, to which is pivotally connected one end of an arcuate spring I84. The opposite end of the spring I84 is pivotally secured upon the side face. of the clutch-member 9| by means of a screw I85. The arcuate spring I84 is provided, intermediate its ends, with a shoulder portion I86 which is adapted to engage the inner face of the circular flange I81 of the clutch-member 9|, thereby to form a fulcrum point for the arcuate spring.

Referring to Fig. 4, the arcuate spring .I 84 and the links |8| and 99 are so proportioned that the projection 98 is normally spring biased into engagement with the recess 91, to the end that the clutch-member 9| and the collar 92 are locked together. Therefore, rotation of the shaft 38 will turn the driving dog which, through the medium of the clutch-member 9| and collar 92, will rotate the shaft 46.

To break the toggle, formed by links 99 and I8I, and reestablish driving relation, a pawl I88 (see Fig. 4) is pivotally mounted upon the pin I82 of the toggle link I8I. The pawl I88 is adapted to engage a shouldered recess I89 in the periphery of the collar 92. A light bow spring I I8, which has one end thereof disposed within an aperture III formed in the arcuate spring I84, yieldingly holds the pawl I88 in contact with the collar 92 by having the bent end portion II2 of the spring I|8 biased against the pawl.

Operation The driving element or dog rotates the clutchmember 9| in the direction indicated'bythe argrow i-n Fig-.4. When an excessive load or torque applied-to the shaft I 46: the wedge-shaped projection-98 sis forced out-of therecess .llinthe collar by -the inclined wall of the recess, thereby straightening the toggle, as shown by dotted lines in'Fig. '4. Preferably, sufiicient momentum is given the toggle when itis straightened to. cause a slight reversebendingtthereof, which is limited by-the projection I I2 formed on thelinleilfl. The effect of this slight reverse-bending ofthe toggle is-tomove the wedge-shaped projection98 on the link Mi-to a position in which itisentirely out of-contact with the-collar 92, as shown in Fig. .4. When the wedge-shaped projection 98 is moved tea-position out of contact with the collar 92, the spring pressed pawl we is moved outwardly. with the link 99; and-the free end of the .pawl rides freely over the periphery of the collar 92 in a counter-clockwise direction as long asthe clutchmember: 9! overruns the collar 92. It. will be observed thatthe free end of the spring I94 acts inwardly and, therefore, tends to break the toggleqbdth inwardly and outwardly. It will be obvious: that the maximum force required, to straighten the toggle is at the beginning of the straightening operation, diminishing as the pivot points-approach alignment.

When it is desired toreestablish driving relation, the drivingdog .and clutch-member 9| are rotated in' the-reverse--direction.- To accomplish this action, the operator need only turn the wheel H; by hand: Whenthe: shouldered recess 109' in the collar. 92, engages theipawl I 93 which is urged inwardly. by the light spring liii,'the pivotal point I52 of'the toggle is pulled inwardly, breaking' the toggle and thereby forcing the projection Elfi onthe link '99 into the wedge-:shaped recess Q'J-inthe collar 92.

In order :to hold the collarv 920m a fixed position'whi'le' resetting the togglarthe above noted clutch+settingwheel '55 'is' provided on the shaft 46: and it is held-rigidly thereon by means of the set-screw The periphery of the wheel 95 is formed'withwa plurality of evenly spaced slots I 13 which are adapted to be entered by a spring retract-ed detent H4 carried in the bed-plate id. By depressing the. detenti Mlagainst, the force of the coils-pring l 85 :to the extent thatthe detent enters one of the slots l 53, the operator effectively locks the shaft 45 and collar 92. The overload release clutch ll may then be readily reset as above described. 7

Thus it is to be understood that in the event either of the rotary hooks becomes jammed, the clutch. ll will disconnect shaft A'a from shaft 38, thereby-to-permit the lower and :upper feeding mechanisms to operate in unison although; the hook-actuating elements have ceased to operate.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine, in combination, a work-support, an endwise reciprocator and laterally vibratory needle, a rotary loop-taker disposed below said work-support and complemental to said needle in the formation of lock-stitches, a rotary actuating shaft disposed below said work-support, work-feeding mechanism, actuating means carried by said rotary shaft for imparting work advancing movement to said workfeeding mechanism, a rotary loop-taker actuating shaft disposed below said work-support, and driving connections spaced from said feed actuating means and including an overload release clutch between said shafts.

2. In a sewing machine, in combination, a

WOIKFSHDDOITU" stitch-:forming.-. mechanism. eluding -a thread-carryin .needle .and arotary loopetaker; 1 means for reciprocating saidneedle, arotaryv actuatingshaft disposed-belowsaid W.0IK+ support, a work-advancing feededog operatin through said WOI'knSUPIJQIt, actuatingmeans carried by usaid rotary shaft for imparting, worl: advancing movement to, said feed-dog, ,a; rotary l 1op.--taker.-.actuating shaft;- disposed .below,-,. said Work-support, driving .connfections, spaced from said feed actuating.means and includingan overloadrelease. clutchbetween saidshafts, andmeans forimnartine *Worhadvancingm m t o. d nerdleiin-run son w th the w k-ad an m ements (ii-said dzdoa 3..i In a qsewing. =machine, in combination, a. work support, stitch-forming mechanism includ-- ns-a r tar ;l m kerz i osedbe ow d wo k: support-and an ndi se, re p c w d ter. ally vibratory; needle, a work adyancing feed-dog operating throughsaid,work-support, a rotary actuating shaft disposed below said work-suDl20rt and comprisingalined feed and loop-taker shaftsections, meansfor rotating said feed shaft-sec tion anti-rating. means carried by the feed shaftsection; for imparting work-advancing movements, to said feed-dog; driving connections spaced-from said feed; actuating. means and comprising an overload release-clutch between said shaft-sections, and operative connections with said ,loop-taker; shaft-section for rotating said loop-taker.

4. In a sewing machine having a frame including .a work-support and an overhanging bracketarm, incombination, an arm-shaitrotatably journaledin said bracket-arm, abed-shaft'rotatably journaled atthe under side of said worksupport, driving connections for rotating said shafts in-unison, a thread-carrying needle, operative connections-with said arm-shaft for imparting endwise reciprocatory work-penetrating and laterallyvibratory work-feeding movements to said needle, a feed-dog operating through said work-support, actuating means carried by said bed shaft for imparting work-advancing movements to saidfeed-dogin timed relation with the work-feeding movements of said needle, a rotary loopta-ker disposedbelow said work-support, a rotary loop-taker actuating shaft journaled belowsaidwork support coaxially with said bedshaft,drivingponnections spaced-from said feed actuating means and comprising an overload release clutch; between said bed-shaft and said loop-taker actuating shaft, and operative connectionswithsaid loop-taker actuating shaft for: rotating, said loop-taker a plurality of times for. eachreciprocation of said needle.

5. .In,,-a sewing machine having, in combination, a work-support, stitch-forming mechanism including a laterally vibratory and endWise reciprocatory thread-carrying needle and a rotary loop-taker, a rotary actuating shaft disposed below said work-support, means for rotating said shaft, work-feeding mechanism, actuating means carried by said rotary shaft for imparting workadvancing movement to said work-feeding mechanism, and a rotary loop-taker actuating shaft disposed below said work-support; the improvement which consists in the provision of an overload release clutch spaced from said feed actuating means and disposed in driving relation between said shafts, said clutch comprising, a rotatable driving element, a rotatable driven element, means for connecting said driving and driven elements, means for moving said connecting means to an inactive position when a predetermined load is applied to said driven element, and a pawl under control of said driven element for thereafter moving said connecting means to its active position.

6. In a sewing machine having, in combination, a frame comprising a work-support and a bracket-arm over-hanging said work-support, a rotary needle-reciprocating shaft journaled in said bracket-arm, a rotary actuating shaft journaled below said work-support and disposed substantially parallel to said needle-reciprocating shaft, driving connections for rotating said shafts in one-to-one relation, an endwise reciprocatory and laterally vibratory needle-bar operatively connected to said needle-reciprocating shaft, a needle carried by said needle-bar, a loop-taker operatively connected to said actuating shaft to rotate a plurality of times for each needle reciprocation, a feed-advance rock-shaft journaled below said work-support and disposed substantially parallel to said actuating shaft, a workadvancing feed-dog operatively connected to said rock-shaft, and means carried by said actuating shaft for imparting oscillatory movement to said rock-shaft; the improvement which consists in the provision of an overload release clutch disposed in driving relation between said loop-taker and said actuating shaft and spaced from said rock-shaft actuating means, said clutch comprising, a rotatable driving element, a rotatable driven element, means for connecting said driving and driven elements, means for moving said connecting means to an inactive position when a predetermined load is applied to said driven element, and means under control of said driven element for thereafter moving said connecting means to its active position.

7. In a sewing machine, in combination, a Work-support, an endwise reciprocatory and laterally vibratory needle, a rotary loop-taker disposed below said work-support and complemental to said needle in the formation of lock-stitches, a rotary actuating shaft disposed below said work-support, a rotary loop-taker actuating shaft disposed in alined relation with said rotary actuating shaft, driving connections including an overload release clutch between said shafts, workfeeding mechanism including a rock-shaft disposed in spaced parallel relation with said rotary actuating shaft, and driving means for said rockshaft, said driving means being carried by said actuating shaft and spaced from said overload release clutch. l

8. In a sewing machine, in combination, a work-support, an endwise reciprocatory and laterally vibratory needle, a rotary loop-taker disposed below said work-support and complemental to the needle inthe formation of lock-stitches, a work-advancing feed-dog operating through said work-support, a rotary actuating shaft disposed below said work-support, actuating means carried by said rotary actuating shaft for imparting work-advancing movement to said feeddog, a loop-taker actuating shaft, driving connections spaced from said feed-advance actuating means including an overload release clutch between said rotary actuating shaft and said looptaker actuating shaft, said clutch being adapted to disconnect said latter two shafts Whenever a. predetermined load is applied to said loop-taker actuating shaft, and means for reconnecting said latter two shafts through said clutch, said latter means including a manually controllable locking device associated with said loop-taker actuating shaft and adapted for locking said latter shaft against rotary movement.

9. In a sewing machine having a frame including a work-support and an overhanging bracketarm, in combination, an arm-shaft rotatably journaled in said bracket-arm, a thread-carrying needle, operative connections with said armshaft for imparting endwise reciprocatory workpenetrating and laterally vibratory work-feeding movements to said needle, a bed-shaft rotatably journaled at the under side of said work-support, driving connections for rotating said shafts in unison, a rotary loop-taker disposed below said worlz-support and complemental to said needle in the formation of lock-stitches, a rotary looptaker actuating shaft disposed in alined relation with said bed-shaft, driving connections including an overload release clutch between said bedshaft and said rotary loop-taker actuating shaft, work-feeding mechanism disposed below said work-support, and actuating means spaced from said overload release clutch and carried by said bed-shaft for imparting work-advancing movements to said work-feeding mechanism in unison with the work-advancing movements of said needle.

HENRY C. NISSEN.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 565,415 Barnard Aug. 4, 1896 1,116,629 Ringe Nov. 10, 1914 1,914,795 Andres June 20, 1933 2,095,450 Myers Oct. 12, 1937 2,098,785 Mathewson Nov. 9, 1937 2,128,031 Myers Aug. 23, 1938 

